Alexander Velitzyn, main character of J. M. Siderova's The Age of Ice, conceived on a bed of ice is immune to cold and when in a state of high emotion his flesh becomes painfully cold to the touch. In time he learns to control this, being able to make ordinary ice diamond hard and to turn water to ice at will. Extreme, as in Arctic level, cold puts him into a state of suspended animation. After doing this once he stops aging, his story extending over 250 years. It is hinted that he may be an incarnation of Old Man Frost.
The eponymous Wintersmith, of the Discworld novel, though this is just a subset of his general "Embodiment of the force of winter itself" bit.
In Thief of Time, we find out that Kaos, the fifth horseman who left before they became famous, has a sword that's so cold it goes beyond absolute zero and generates a sort of "burning cold" anti-heat. He uses it to keep milk fresh by putting it in the same room as a super-hot burning furnace.
In The Divine Comedy, The Devil is the originator of the blizzards which freeze the final circle of Hell. Thanks to the winds from his six wings, thousands upon thousands of traitors are frozen with him in Lake Cocytus, forever to hate each other for eternity.
Harry also figured out that he can adjust his fire spells to draw heat less evenly from the surroundings and, a couple of times, uses this to freeze water.
After he took Mab's offer of becoming the Winter Knight, Harry has been able to use ice-related spells much more. It was hinted that his new mastery of ice and his old mastery of fire are significant somehow.
The villain of Caroline Cooney's Freeze Tag combines this oddly with Taken for Granite—her basic schtick is that if she touches you, she renders you frozen and immobile, apparently forever, while fully conscious and aware. She never actually kills any of her victims and, at several points, undoes the effect just to toy with them. (This leads to part of the conflict over whether or not to kill her—if she can't be redeemed, a lot of people will stay frozen.)
The Jaghut have powers connected to ice, cold and death — possibly also giving them a limited control of time. They have their own Warren (Path of Magic) called Omtose Phellack, also known as the Hold of Ice, and are fond of calling down ice ages. Elder God Mael calls ice 'the Jaghut answer to everything'.
The Stormriders combine this with Ice Magic Is Water. They are a mysterious people living in a deep ocean trench, only appearing during storms, sheathed in ice armour and riding hybrid-mounts made of water and ice. They may be connected to the Jaghut.
The Clayr of the Old Kingdom trilogy, though primarily a clan of all female clairvoyants, use ice to amplify their Sight, hence why they live in a Glacier. When away from the glacier, they use spells to create a screen of ice on which they project their Sight, so as to show others.
Ilke in Phenomena, she was given some of the spirit of a Frost spirit and can use most powers related to frost, like ice and snow.
In the Rainbow Magic series, Jack Frost, the goblins, and some of the fairies all have ice magic.
In The Singer of All Songs, there are several kinds of chantments (magic songs). The Daughters of Taris, an all-female religious order, can sing the chantments of ice, and they protect their territory with a giant ice wall. Instead of combining with water (indeed, it's noted that the ability to swim isn't particularly common among them), the High Priestess also bears and passes on the knowledge of the chantments of ice that invoke darkness, the opposite of the chantments of fire which also have power over light.
"The Snow Queen." She seems to be a member of The Fair Folk, with similarly inscrutable motives; she rules a race of creatures who resemble snowflakes, and lives far north of our heroine.
The Others from A Song of Ice and Fireare the ice. They're associated with the perpetually frozen far north, appear with the worst weather winter can bring — unless the winter follows them — and even seem to be made of ice, melting when they die, and come equipped with armour and weaponry made of magically altered ice. They embody the Evil Is Deathly Cold aspect of this trope, seeking to plunge the world into an endless winter and killing every living human they come across, reanimating them as mindless Wights under their command. They are also associated with "giant ice spiders" in legends. Whatever those are.
In the short novel, The Ice Dragon, which provided some inspiration for A Song of Ice and Fire, the main character, Adara, is a young girl who was born during the coldest winter in living memory, and somehow winter had left its mark upon her. Many readers have noted that she bears a resemblance to the Others. Though she does not have any active powers, she has a strong affinity for the cold and can stay outside during winter without it even bothering her. Her skin is also pale and cold to the touch, on top of having a fittingly icy personality brought about by her unusual condition. On top of all this, she is capable of riding the titular ice dragon, which has plenty of icy powers of its own.
The first spell Grumph casts in Spells, Swords, & Stealth is an ice spell, used to assist Thistle in their first real fight as adventurers. In the second book, Grumph puts the ice spell to creative use during his mage trial by casting it on himself when he has to cross an obstacle hot enough to knock him out if he went unprotected.
Super Powereds has Michael Clark, who can throw blue bolts that freeze anything they hit. He throws them by punching towards the target. He can also form an armor of ice to protect himself, regenerating it as it melts or takes damage. He's a bit of a bully and has a hard time coping with the fact that he's no longer the strongest of his peers (as he was in his hometown). Ever since his first match with Vince, he holds a deep grudge towards him despite the fact that he won that fight. Michael convinces himself that Vince humiliated him by not charging up before the fight and nearly beat him with what Michael considers a sucker punch. By Year 2 he is still under the mistaken assumption that he's better than Vince when, in fact, Vince has left him far behind and doesn't even consider beating Michael to be a challenge. It helps that while Michael's ice armor may provide some resistance against Vince's fire blasts, it does nothing to hinder an electrical blast and Michael didn't know that Vince could absorb and emit other kinds of energy.
Blizzard in Tales of an Mazing Girl can create ice with his gun. He is of course named after the video Game company, Activision/Blizzard.
Twilight Dragon has Princess Atoli, who is specifically known as the Sorceress of Snow.
The winter court in the Wicked Lovely series. Specifically, Beira the winter queen and Donia the winter girl. Donia later becomes the next winter queen after Beira's death. Her icy nature is caused by bitterness about being forced to become the winter girl, and thus not being able to be with her love, Keenan, the summer king - their very natures are incompatible, although it is implied that, after Beira's death, they at least try. I would imagine it would be painful; Keenan would end up covered in frostbite and Donia in burns.
Icewing drgons in Wings of Fire are well-suited for living in cold environments. This includes the ability to breathe a deadly freezing breath.
The Wizard of London: After her pact with the Ice Dragon, Lady Cordelia is basically a mage version of this. David is well on his way to becoming one as well.